How to capture the IP Address of the Oracle client making the data request

The key player is SYS_CONTEXT as in:

Select SYS_CONTEXT('USERENV','IP_ADDRESS') FROM dual

Here's a trigger that captures the ip addresses of clients deleting rows from a table:

CREATE OR REPLACE TRIGGER "MYSCHEMA"."SESSIONWATCHER" BEFORE
DELETE ON "MYSCHEMA"."CURRENTUSERSESSION" DECLARE

SInfo MYSCHEMA.SESSIONHISTORY.INFO%TYPE;
BEGIN
SELECT SYS_CONTEXT('USERENV','IP_ADDRESS') INTO SInfo FROM dual;
INSERT INTO MYSCHEMA.SESSIONHISTORY VALUES (SInfo);
END SessionWatcher;